摘要:

The age of the oldest polders in the Netherlands is historically proved to be about 1000 years. Soil development varies widely depending upon soils development before embankment, drainage, land use, and age and composition of parent materials. Nearly all the pedological processes may be included into the initial soil formation called “ripening.” The parent materials are divided into three main groups: peaty, calcareous mineral, and noncalcareous mineral. The behavior of each group under the ripening process is very different. Ripening causes important changes like subsidence, increased permeability, and development of cambic horizons. Such widely different soils as, for example, Eutrochrepts, soils with natric horizons, or acid sulfate soils may be formed by ripening.Umbrie and Mollic epipedons may form rapidly by decomposition of organic surface layers.

ISSN:0038-075X    

出版商:OVID    

年代:1973

数据来源: OVID

摘要:

Evidence for Quaternary environmental changes in southern Africa has been obtained from palynologic, geomorphologic, and pedologic studies. It appears that in the Vaal and Orange drainage of the interior (26–30°S) colder periods with heavier precipitation alternated with wamer and drier periods, broadly synchronous with glacial and nonglacial trends in high latitudes of the northern hemisphere. By contrast, pedogenesis in the coastal regions (32–34°30′S) corresponded with warmer climates, whereas colder phases were relatively dry.

ISSN:0038-075X    

出版商:OVID    

年代:1973

数据来源: OVID